Creating a Climate Zone Map for Mechanistic Empirical Pavement Designs

Abstract

The Enhanced Integrated Climate Model (EICM) in the MechanisticEmpirical (ME) Pavement Design software is an integral part of the ME pavement design process. EICM has a national weather database with hourly data from approximately 800 weather stations for at least 60 months. EICM uses the included historical hourly weather data to model future climatic conditions for accurate prediction of pavement distresses. Recently, many state departments of transportation started to enhance these weather station data by adding more weather stations and/or expanding the number of months of available data. The goal of these efforts is to utilize a weather station very close to the project site and include more historical weather data. In the ME Pavement Design software virtual weather stations can be created by selecting up to six weather stations to model climate change in the vicinity of the project site. However, without having extensive knowledge on regional climatic patterns, the pavement designer may not select the most appropriate weather stations to represent site specific climate conditions. Many states have microclimates due to different geographical or environmental conditions. This paper examines the use of Geographical Information System (GIS) to create a local climate zone map to aid pavement designers to select the most appropriate weather stations for pavement designs. Four climate zone maps were developed using the average low temperatures in January, average high temperatures in July, average precipitation in January and average precipitation in July for the I-94 corridor in Michigan as a case study. Further, the combined effects of these variables were examined by combining above individual climate zone maps into a single composite map using Inverse Distance Weighted (IDW) techniques. The maps show localized climate zones even within the same county highlighting the need of using appropriate weather stations to correctly model the climatic effects in pavement performance. The use of the developed methodology was demonstrated by comparing pavement performance results for a same pavement structure located in different climate zones using MEPDG software.